Hydraulic flow-regulating device



Patented Oct. 29, 1935 UNITED STATES HYDRAULIC FLOW-REGULATING DEVICEJohn Warren Watson, Wayne, Pa., assignor to John Warren Watson Company,Philadelphia, Pa., a corporation of Pennsylvania Application March2,1933, serial No. 659,428

Claims.

This invention relates broadly to improvements in the means forrestricting and resisting the flow of a liquid from one chamber toanother.

A particular object of the invention is to pro- 5 vide a form ofrestriction or valve which will resist, with minimum variation, the flowof liquids of varying viscosities.

The viscosity of the oils used, for example, in hydraulic shockabsorbers varies with every change in temperature. Heretofore, with arestriction or orifice of fixed area, these changes in viscosity whichbring about changes in coefficient of friction resulted in very markedchanges in the resistance to the flow of the liquid and 151 hence in theresistance producedby the shock absorber.

, To overcome these objections and to provide a more or less constantresistance to the flow of liquids of varying viscosities, it has beenthe practice to vary the area of the restriction as for example by meansof thermostatically actuated valves.

I have found that very uniform results, despite widely varyingviscosities, may be obtained even with a restricting orice of xed area.I accomplish this by forming the fixed area in a manner which reduces toa minimum the items of friction. There are two items of friction set upin forcing a liquid through a restricting orifice. One item is that ofskin friction between the oil and the orice wall and the other item isfriction within the oil itself caused by turbulence.

In the forms of restricting oriiices illustrated in the presentembodiment of my invention it will be seen that both of these frictionitems have been reduced to a minimum. Hence it is that changes inviscosity and co-enicient of friction have so little eiect on theresistance to flow. To take care of the first item of friction, skinfriction, I have 'reduced the length of wall area to a mere line. Inother words, the wall area at the point of restriction has no length. Totake care of the second item of friction, internal friction aggravatedby turbulence, I have provided for a true stream line of ow as theliquid enters and leaves the restriction and thus reduce cross currentsand turbulence of ilow.

Two embodiments of my invention are shown' in the accompanying drawingin which Figure 1 is a sectional view of a shock absorber of more orless conventional design well known in the shock absorber art, and Fig.2 is a fragmentary sectional View illustrating a preferred form of xedorifice. This design is diagrammatic merely to serve the purpose ofshowing (Cl. 18S-89) I employ the ball member 6 in the passage 5--5 10the length of the wall area of the governing restriction has beenreduced to a mere line (indicated in broken line at I4) which of courseis the minimum length possible. Also the ball provides a perfect streamline flow and thus re- 15 l duces turbulencetoa minimum. The position ofthe ball may be adjusted with relation to the tapered portion of passage5--5 in a manner to get any desired area of orifice and hence anydesired velocity of flow to bring about the re- 20 quired resistance.Thi's desired positioning of the ball is accomplished by screwing pinmember 'I in or out in the threads provided for that purpose. 8 is apacking member and 9 a gland for tightening the packing around pinmember 'I. 25 The ball is now shown in position to resist flow of theliquid from chamber I to chamber 2 as the oscillating vane 4 is rotatedin a counterclockwise direction. When the oscillating vane 4 is rotatedin a clockwise direction the flow 30 of liquid is then from chamber 2 tochamber I which moves the ball over against pin I0 which, like pin 1,may be adjusted to hold the ball in any desired position along thetapered passage and thus `set up the desired velocity of flow in 35 thatdirection and hence the desired resistance to movement of theoscillating vane in the clockwise direction. Passages II and I2 in pins1 and I0 respectively are for the purpose of unbalancing the pressureson the front and back of 40 the ball in order to hold the ball snuglyagainst the pin and thus prevent it from gyrating and causing noise.

To suit the invention to some other arrangement of parts as may begoverned by the specific 45 shock absorber or other hydraulic device,where it may not be practical or desirable to use the ball shapedrestriction, the'same minimum' of wall length of the governingrestriction, and the sameV freedom from turbulent ow may be ac- 50complished by rounding out or counter-sinking a hole through any wall orplate member dividing the chambers as is here, by way of example,alternately shown at I3 in wall 3 of Fig. 2. According to the thinnessof such a dividing wall 55 or plate or to the depth of rounding orcountersinking, the wall length of the governing restriction may bebrought down to the very minimum of a line, as indicated at Ida, or toany desired or practical degree approaching that minimum.

Having thus illustrated and described my invention, what I claim anddesire to protect by Letters .Patentof the United rStates is:

1. In mechanism rior resisting a `Iforce, Afltwo chambers, a passageconnecting said chambers, a liquid in one of said chambers, means. forcausing said liquid to ow from said chamber through said passage to saidother chamber, a'restrc'iing orice of constant area in said ,passage to:govern said flow, said passage having :a -Wall :portion curvingcontinuously toward and up to said 12estricting ori'ce, and means insaid passage constructed and arranged to unbalance the pressures at eachside of said continuously acurving Wall portion. y

2. 'In 'mechanism for resisting a torce, vtvvo chambers, a passageconnecting said ham'bers, aliquid in one of the chambers, mea-ns'orpausing said liquid to iiow `from sa'id 1chamber through saidlpassage "to th'eother chamber, a1-'estrictin'g orice 'of constant areaiin the vpassage togovern -said ViioW, means in said passage providing acontinuously curving wall'potion' therein toward and tup to 'saidrestricting 1orifice, mid means in lthe passage operable to -unbalance-the pressures at each side 'of said last Lmentioned means. i Y

'3.'I-n mechanism for resisting "a force, two

, chambers, Ia passage `corn-resting saidphambers,

aliquid in'one of the chambers,'means forcausing :said liquid to '-iiowfrom said `chamber through l'said passage to fthe -other chamber, ya

restricting orice of constant area in the passage to govern said flow,means movable in said passage and providing a continuously curving wallportion therein toward and up to said restricting orice, means limitingmovement of said last mentioned means, and means associated with saidlimiting means operable to unbalance the pressures at each `side kof,the tmeans providing the continuously vcurving wall portion in saidpassage.

I4. In a mechanism for resisting a force, two chambers, a passageconnecting said chambers,

4a liquid in one :or 'the chambers, means for causing said liquid to oWfrom said chamber `throi1gh-saif3. -passage to the other chamber, arestrictingorice of iconstant area in the passage to govern said oW, aball movable in said passage andproviding a continuously curving Wallportion :therein toward and up to said restricting orice, and means alsoin the passage operable to Fimbalance fthe 'pressures at leach :side ofsaid ball.

5. In a mechanism fior resisting a force, `tvvfo chambers, a=passageconne'ctingsaid chambers, a liquid iin fone fo the chambers, means foricausing -saidliquid to flow iromsaid fchamber ithrough said passage tothe other chamber, a restricting orice 0I constant area i-n Ithe passageto govern said iiow, labail `movable in said passage and 'providin'g =acontinuouslyfcurving wall 'portion th'erei-n ftowardfand up to -fsaidrestricting orifice, and' means lfor adjustably Tlimiting movement ofAsaid ball, @said "last mentioned 'means having passages therein.operable 'to imbalance 'the :pressures at each vsi'sle 1 of lthe "ball,

E-N WARREN `WATSON.

